VOA慢速英语:北约悄悄地纪念70周年

bloc –n. a group of countries connected by a treaty or agreement

obsolete –adj. no longer used

adapt –v. to change in order to operate better or to be better able to meet needs

cyber –adj. related to computers and computer networks

confidence –n. the belief that someone has the ability to succeed at something

frustration –n. a feeling of annoyance at not being able to or being prevented from reaching some outcome